CN100366399C

CN100366399C - Electric tool torque controlling device

Info

Publication number: CN100366399C
Application number: CNB2005100772972A
Authority: CN
Inventors: 钟福祥
Original assignee: Techway Industrial Co Ltd
Current assignee: Techway Industrial Co Ltd
Priority date: 2005-06-16
Filing date: 2005-06-16
Publication date: 2008-02-06
Anticipated expiration: 2025-06-16
Also published as: CN1880027A

Abstract

The invention relates to an electric tool torque controller. A switch circuit is arranged at the place between a motor and a direct current power supply, the change station of voltage and current between the motor and the direct current power supply detected by a voltage sensing circuit or voltage and circuit change time is converted into a torque detecting value through a torque sensing circuit and is transmitted into a single chip processor to be compared with a preset torque value; when the torque is larger than the preset torque value, the single chip processor closes a switch circuit, the connection between the motor and the direct current power supply is cut off, and thereby, the efficacy of preventing the motor from burning can be achieved.

Description

Electric tool torque controlling device

Technical field

The present invention relates to a control device, refer to a kind of electric tool torque controlling device especially.

Background technology

So-called electric tool; work such as promptly refer to make the user can finish boring easily or to screw togather by electrical motor driven one tool heads; and because corresponding its of each tool heads uses object that different best torsion all should be arranged; so existing general electric tool; all can adjust its suitably corresponding torsion at different tool heads; and in using in case meet with when surpassing it and setting torsion originally, even the temporary disengaging motor of tool heads drives with protection tool heads and motor.

Existing common electric tool is in mechanical mode, utilizes the pressure that changes a spring to preset torque magnitude, and by this spring is bestowed pressure, tool heads is sustainable to be driven by motor and make; So when meeting with, then the driving of the temporary disengaging motor of tool heads be can make, and then protection tool heads and the purpose of avoiding motor to burn out reached because of the drag of spring above setting torsion.

Only above-mentioned mode still has following shortcoming, and one is difficult for accurately being adjusted to required torque magnitude in fact for to adjust torque magnitude by spring being bestowed pressure; Another then when surpassing it in using and set torsion, only makes tool heads break away from the driving of motor, does not make motor stop, and so motor still can continuing spinning, and is except that consuming meaningless electric energy, also influential to the life-span of motor.

Hence one can see that, and the control device of an electric tool if can be provided, and it can be set its required torque magnitude accurately, and when surpassing its setting torsion in the use, can reach protection tool heads and the purpose of avoiding motor to burn out by the rotation that stops motor.

Summary of the invention

Main purpose of the present invention is to provide a kind of can accurately set torque magnitude according to actual demand, and can protect motor to avoid the electric tool torque controlling device that burns out.

For reaching the major technique means that above-mentioned purpose takes is to make above-mentioned control device include:

One on-off circuit is connected between a dc source and the motor;

One single-chip processor, the one output connects described on-off circuit, to control the switching of this on-off circuit;

One voltage checking circuit, its input are connected between dc source and the motor, to detect the changing condition of motor load voltage;

One torsion checking circuit, its input is connected with described voltage checking circuit, and its output then is connected with described single-chip processor, the changing condition of motor load voltage can be converted to the actual torque value of motor, and the input single-chip processor;

One torsion setting unit is that its output is connected to described single-chip processor for the default torque magnitude of user.

When described control device cooperates an electric tool to use, can utilize the earlier default torque value in torsion setting unit; When to be used, the voltage checking circuit obtains the variation of load voltage, electric current by the change of voltage between motor and dc source or utilizes the change frequency of voltage in the unit interval, electric current, converts the value of reaction motor torsion variation to and imports single-chip processor by the variation of torsion checking circuit with load voltage again; Single-chip processor is according to the torque value that is set by the torsion setting unit; make comparisons with the detected value of importing by the torsion checking circuit; torsion when electric tool is worked is during greater than default torsion; even the single-chip processor on-off circuit cuts out, and then cut off the effect of protecting motor and tool heads to reach that is connected of motor and dc source.

The present invention further comprises a display, and wherein the input of this display is connected to described single-chip processor, the torque magnitude that sets in order to demonstration.

The present invention further comprises a high pressure checking circuit and a low pressure checking circuit, wherein this high pressure checking circuit is connected with described voltage checking circuit respectively with the input of low pressure checking circuit, output then is connected to described single-chip processor respectively, works under dc source overtension or excessively low situation in order to the restriction motor.

Description of drawings

Fig. 1 is a basic framework schematic diagram of the present invention.

Fig. 2 is the circuit diagram of a preferred embodiment of the present invention.

Fig. 3 is the circuit diagram of another preferred embodiment of the present invention.

10,10 ' on-off circuit

11,11 ' driving transistors

12,12 ' switching transistor

20,20 ' single-chip processor

30,30 ' voltage checking circuit

40,40 ' torsion checking circuit

50,50 ' high pressure checking circuit

60,60 ' low pressure checking circuit

70,70 ' torsion setting unit

71 change-over switches

72,72 ' torsion setting circuit

73 variable resistors

80,80 ' display

The specific embodiment

As shown in Figure 1, disclose the basic framework schematic diagram that electric tool torque controlling device of the present invention is arranged, it includes:

One on-off circuit 10 is to be connected between a motor and the dc source, and in present embodiment, this dc source is a battery;

One single-chip processor 20, its output is connected to aforementioned switches circuit 10, controls the switching of this on-off circuit 10;

One voltage checking circuit 30, its input are connected between motor and the dc source, in order to the voltage that detects motor load, electric current variation or the change frequency of voltage, electric current in the unit interval;

One torsion checking circuit 40, its input is connected to aforesaid voltage checking circuit 30, and its output then is connected to aforementioned single-chip processor 20, converts the size of the actual torsion of motor in order to the voltage change with motor load, and imports single-chip processor 20;

One high pressure checking circuit 50, its input connects aforesaid voltage checking circuit 30, its output then is connected to aforementioned single-chip processor 20, in order to the magnitude of voltage and a reference voltage of dc source are made comparisons, when the voltage of dc source during, then make single-chip processor 20 that on-off circuit 10 cuts out greater than this reference voltage;

One low pressure checking circuit 60, its input is connected with aforesaid voltage checking circuit 30, its output then is connected to aforementioned single-chip processor 20, in order to magnitude of voltage and another reference voltage of dc source are made comparisons, when the magnitude of voltage of dc source during, then make single-chip processor 20 that on-off circuit 10 cuts out less than this reference voltage;

One torsion setting unit 70, its output are connected to aforementioned single-chip processor 20, are sent to single-chip processor 20 in order to the torque value that the user is preset;

One display 80, its input is connected with aforementioned single-chip processor 20, in order to show default torsion.

Be illustrated in figure 2 as the detailed circuit diagram of a preferred embodiment of the present invention, on-off circuit 10 comprises a driving transistors 11 and a switching transistor 12, and wherein driving transistors 11 is a BJT, and switching transistor 12 is a MOSFET; The base stage of driving transistors 11 is to be connected to single-chip processor 20 by a resistance R, and colelctor electrode then is connected to the grid of switching transistor 12, and switching transistor 12 is to be connected between dc source and the motor with leakage, source electrode.When single-chip processor 20 output high potentials made driving transistors 11 conductings, switching transistor 12 also was switched on, then the sub-motor of DC power supply; Otherwise, when driving transistors 11 by the time, then switching transistor 12 cuts out, this moment the dc source motor of stopping power supply.

Voltage checking circuit 30 is made up of divider resistance R1, R2, and resistance R 1 is to be connected between dc source and the on-off circuit 10 with respect to the other end of dividing potential drop node, and the dividing potential drop node of itself and resistance R 2 junctions then constitutes an output.

Torsion checking circuit 40 comprises one by a RC circuit and an OP amplifier U2B that R3 and C1 formed, and wherein the back coupling of the output of this OP amplifier is connected to the negative terminal input and constitutes a buffer.

High pressure checking circuit 50 is a comparator that is made of OP amplifier U1B; export the negative terminal input that a voltage gives comparator by the output of aforesaid voltage checking circuit 30; a reference voltage is then imported in anode input in comparator; when the output voltage of voltage checking circuit 30 greater than reference voltage; then comparator output terminal forms electronegative potential on the corresponding pin of single-chip processor 20; inform the overtension of dc source this moment, thus on-off circuit 10 cuts out, so that high voltage protective to be provided.

Low pressure checking circuit 60 is a comparator that is made of OP amplifier U3B; export the anode input that a voltage gives comparator by the output of aforesaid voltage checking circuit 30; another reference voltage is then imported in negative terminal input in comparator; when the output voltage of voltage checking circuit 30 less than this reference voltage; then comparator output terminal forms electronegative potential on the corresponding pin of single-chip processor 20; inform the brownout of dc source this moment, thus on-off circuit 10 cuts out, so that low-voltage variation to be provided.

Torsion setting unit 70 switches switch 71 by one and a torsion setting circuit 72 is formed, wherein torsion setting circuit 72 is made of a plurality of resistance, when the different contacts of change-over switch 71 are connected, the corresponding pin of single-chip processor 20 will present different potentials, to reach the purpose of setting torsion.

Display 80 is a seven-segment display, and its input is connected to aforementioned single-chip processor 20.

As shown in Figure 3, detailed circuit for another preferred embodiment of the present invention, its structure is roughly the same with last embodiment, difference is in torsion setting unit 70 ' to be made up of a variable resistor 73 and a torsion setting circuit 72 ' institute, wherein this torsion setting circuit 72 ' comprises one by a RC circuit and an OP amplifier U4B that R6 and C2 formed, and wherein this OP amplifier is to make output feedback be connected to the negative terminal input and constitute a buffer.

From the above, by means of described voltage checking circuit and torsion checking circuit, variation that can be by voltage, electric current between motor and dc source or utilize the change frequency of voltage in the unit interval, electric current, and learn the torque magnitude of motor this moment; Single-chip processor is then according to being made comparisons by default torsion in torsion setting unit and the motor torsion that is detected by the torsion checking circuit; if motor torsion is greater than the torque magnitude of setting; then cut off output and make not conducting of switching transistor in the on-off circuit; make to form between motor and the dc source and open circuit, so that motor and tool heads are constituted protection.

Claims

1. an electric tool torque controlling device is characterized in that, includes:

One on-off circuit is connected between a dc source and the motor;

One single-chip processor, its output connects described on-off circuit;

One voltage checking circuit, its input are connected between dc source and the motor;

One torsion checking circuit, its input is connected with described voltage checking circuit, and its output then is connected with described single-chip processor;

One torsion setting unit, its output is connected to described single-chip processor;

One high pressure checking circuit is a comparator that is made of the OP amplifier, and the output of described voltage checking circuit is the negative terminal input that is connected to comparator, and a reference voltage is then imported in the anode input of comparator, and output is to be connected to single-chip processor;

One low pressure checking circuit is a comparator that is made of the OP amplifier, and the output of described voltage checking circuit is the anode input that is connected to comparator, and a reference voltage is then imported in the negative terminal input of comparator, and output is to be connected to single-chip processor.

2. electric tool torque controlling device as claimed in claim 1 is characterized in that, wherein:

Described on-off circuit comprises a driving transistors and a switching transistor, the base stage of this driving transistors is to be connected to single-chip processor by a resistance, colelctor electrode then is connected to the grid of switching transistor, and this switching transistor is to be connected between dc source and the motor with leakage, source electrode;

Described voltage checking circuit is made up of divider resistance R1, R2, and resistance R 1 is to be connected between dc source and the on-off circuit with respect to the other end of dividing potential drop node, and the dividing potential drop node of itself and resistance R 2 junctions then constitutes an output;

Described torsion checking circuit comprises a RC circuit and an OP amplifier, and its input is connected with described voltage checking circuit, and its output then is connected with described single-chip processor, and wherein the back coupling of the output of OP amplifier is connected to the negative terminal input and constitutes a buffer.

3. electric tool torque controlling device as claimed in claim 1 or 2 is characterized in that, further comprises:

One display, its input is connected to single-chip processor.